Why did my state tax return not include information regarding subtraction from income for CollegeInvest contribution

It depends. I tested this in my program and it works well.

1. Open up Turbo Tax and start preparing your Colorado  state return.
2. Answer the preliminary questions and continue to a screen that says Here's the income that Colorado handles differently.
3. Go to education>529 College Invest Program Contributions
4. Answer the questions. Once done, the contribution will appear in line 8 on Form 104AD.